21490109029 has 4 divisors (see below), whose sum is σ = 21544240684. Its totient is φ = 21435977376.

The previous prime is 21490109027. The next prime is 21490109033. The reversal of 21490109029 is 92090109412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16769732004 + 4720377025 = 129498^2 + 68705^2 .

It is a cyclic number.

It is not a de Polignac number, because 21490109029 - 2¹ = 21490109027 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21490109027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27065232 + ... + 27066025.

It is an arithmetic number, because the mean of its divisors is an integer number (5386060171).

Almost surely, 2^21490109029 is an apocalyptic number.

It is an amenable number.

21490109029 is a deficient number, since it is larger than the sum of its proper divisors (54131655).

21490109029 is an equidigital number, since it uses as much as digits as its factorization.

21490109029 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54131654.

The product of its (nonzero) digits is 11664, while the sum is 37.

The spelling of 21490109029 in words is "twenty-one billion, four hundred ninety million, one hundred nine thousand, twenty-nine".